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Low hot water pressure to mixer tap from bath (help)
We have a gravity-fed plumbing system in the house, the hot water tank is in the airing cupboard, same floor as bathroom. Cold water tank in loft above. Due to being older house the cold is supplied by the mains.
We now have the shower mixer tap attached to the bath feeds, but if you adjust the thermostat to cold its powerful, if you mix halfway or hot the pressure drop right off and then pulses.
1/ Fit a single hot water negative pump to increase pressure
2/ New feed from cold tank to bath, then new feed from hot water tank to bath with twin pump installed (equal pressure)
My question is (2) sounds the best option, but sounds a bigger job with plumbing, bigger pumps as will be running the bathroom not being connected to mains.
Option (1) sounds more cost affective for my 10 minute shower, but one plumber said it would be fine, but not as good as option (2). The second plumber said (2) only as soon as the mixer tap is opened the mains will flow down the hot pipe causing the pump to stop.
I am sure you all have different views, but it's driving me up the wall
The best way is to fit a negative head whole house pump which is designed to work against mains pressure. Or fit a twin pump to feed the bath/shower mixer tap so the pressure is equal but you will have to make sure the cold water storage tank is big enough to supply it as per manufacturers instructions.
Hope this helps.
Answered 14th Nov 2017